Flutter teams build and better products

October 24, 2019
Flutter teams build and better products

@ codemotion Milan 2019

Flutter, now one year stable, is becoming the de facto standard for multi-platform apps. But what does this mean for companies and agencies? A huge opportunity to build better products! Combining teams which usually never touch each others code creates friction. But given all the benefits of a large diverse team, working on the same codebase is definitely worth it. Learn from teams which actually moved from native to Flutter and their best practices.


Understanding Declarative UI – The hype of React, SwiftUI, Flutter and Jetpack Compose

August 6, 2019
Understanding Declarative UI – The hype of React, SwiftUI, Flutter and Jetpack Compose

@ Talk im Park #4

SwiftUI and Jetpack Compose are the latest additions to native iOS and Android development. Both are UI frameworks which feature a declarative style, similar to React and Flutter.
The transition from imperative to declarative UI is huge. It requires a mindset change! Instead of mutating individual widgets you have to define states and render them. Which first might seem like a weakness and way too much boilerplate code is the biggest strength of that design.
The old, imperative way of writing user interfaces is still used in millions of apps. Your codebase is most likely one of them! This talk will show you a migration path to prepare your apps for declarative UIs until SwiftUI and Jetpack Compose become stable.
Although all those frameworks let you define UIs in a declarative way, there are huge differences in how they work internally. It’s not fair to compare them, since they are designed for different platforms. But this doesn’t mean interesting facts and differences in their implementation can’t be pointed out.

Step up your tooling

July 3, 2019
Step up your tooling

@ Droidcon Berlin 2019

GitHub, Slack, Jira, SourceTree, Jenkins, Sketch… RING!, RING! 2015 Called! It wants its software stack back.
Remember when you switched from Eclipse to Android Studio? It wasn’t easy but totally worth it. To be productive you can’t test every new tool out there. At some point, you have to stick to what you got and over time you forget about the workarounds you’re doing every day.
I did test tons of programs and present you 10 new tools for developers you don’t want to miss for a productivity boost. It’s time to bump up your software stack!

Dart 2.3

May 22, 2019
Dart 2.3

@ flutter.school, Düsseldorf

Small introduction into the latest changes in Dart 2.3. This releases addresses Flutter developers daily challenges with the dart language. The new language features makes it easy to build user interfaces without the need for a markup language. Welcome spread operator, collection if and collection for.

Flutter Study Jam / Hot Reload Hackathon for Beginners

March 12, 2019
Flutter Study Jam / Hot Reload Hackathon for Beginners

@ flutter.school, Cologne

This event is for you if you are new to Flutter or just starting out (for sure you can also join when you are already an expert) and want to build your first app for Android and iOS.

We will start around 4pm at the grandcentrix headquarter in Cologne where Pascal and I will give a short intro to Flutter. You’ll be instructed to build a Flutter app beyond “Hello World”.

We’ll clone a popular app together with Firebase, and fancy animations. From zero to hero in only a few hours!

Continuous Integration with Flutter

February 26, 2019
Continuous Integration with Flutter

@ flutter.school, Düsseldorf

Introduction into CI with Flutter. A presentation about the tools used to make CI with Flutter a success. Lint, code-coverage until automatic publishing to the stores.

CI with Flutter, done right

February 12, 2019
CI with Flutter, done right

@ mobile.cologne, Cologne

Talk about building CI for Flutter apps, independent of the underlying CI environment. I demonstrate Jenkins and Gitlab as examples.

Build, test and static analysis like lint and code coverage included.


Heavy lift work in Flutter – get started with Isolates

October 12, 2018

@ DevFest Ukraine 2018, Lviv

Moving work off the main thread prevents frame drops and makes users happy. Starting with Android P, apps will crash if they are not responding forcing developers to address this problem even more. Working with threads and async computations is every mobile developers daily challenge.

Flutter uses Dart, which is single threaded and has no APIs to start a new threads like in Java or Swift. How does this fit in a world of phones with at least 4 CPUs?

This talk will explain the Flutter threading model, how Futures keep the app responsive on a single thread and how you can use all CPU cores for compute heavy task via Isolates.

Flutter Introduction & Codelab

June 13, 2018
Flutter Introduction & Codelab

@ GDG Nuremberg Android

Flutter Google Developer Expert (GDE) Pascal Welsch will pay us a visit and introduce us in his talk to Flutter.

What’s new about Flutter? Why is it not just another cross-platform development tool? When does it make sense to use it? There are definitely a lot of questions which Pascal will be able to answer.

Afterwards, we’ll do a Codelab on Flutter.

10 years Android – what’s next? Fuchsia and Flutter

March 1, 2018

@ mobile.cologne, Cologne

The Android UI evolved a lot in the last decade. With Holo, Android became kind of nice looking and with Material Design, Android became beautiful. What hasn’t changed is the UI Framework where layouts are inflated, layouted and measured on the main thread. Decisions made in 2005 which can’t be changed now. This makes it harder than it should to run you app constantly on 60fps.

Flutter, a mobile app SDK from Google is designed to render your app constantly at 60fps. It already comes with a rich catalog of pixel perfect Material Design which look and feel like widgets from the Android design support library. Flutter apps are written in Dart and cross compile to Android and iOS to native code (not JavaScript!!!). Java glue code is only required when you’re talking to system services like GPS or notifications.

Flutter could be Googles transition plan for Fuchsia, Googles next operating system for mobile devices. Instead of supporting Android Apps on Fuchsia, apps for Fuchsia can be compiled to iOS and Android apps. Fuchsia supports Dart as first class language and the system UI is written with flutter.

It’s time to look what’s next!

even earlier

ThirtyInch – Introduction to the MVP library

December 11, 2017

@ GDG Düsseldorf

Testing on Android is hard. Activities aren’t really testable, and if not as unit test on the JVM. But with a clever abstraction, most of our UI logic actually can be tested. This talk introduces ThirtyInch, a MVP library for Android.
It compares ThirtyInch to other MVP implementations existing in the wild which often try to be stateless. ThirtyInch tries to be stateful and outlives the Activity lifecycle during configuration changes.

Please keep in mind, this was before Google Announced Architecture Components and ViewModels. ThirtyInch Presenters where back then, the ViewModels you know today from Android Jetpack.

Kotlin in production – One year later

July 13, 2017
Kotlin in production – One year later

@ GDG Düsseldorf

Thanks to the community, Kotlin became the new language for Android Apps. Pascal Welsch is already using Kotlin for over an year in production and will talk about his learnings covering features and tools you should use and other which are too risky for a long term project.Thinking about adopting Kotlin in your project? Pascal shows the process of adopting Kotlin in all Android Apps at grandcentrix.

Introduction to Bluetooth 5

February 15, 2017
Introduction to Bluetooth 5

@ GDG Düsseldorf

Bluetooth 5 -> The Bluetooth SIG released the specification of Bluetooth 5 in December ’16. This release will lay the foundation of future IoT devices: longer range (4x), faster speed (2x), bigger messages (8x)

Pascal Welsch from Grandcentrix will cover the new possibilities, backwards compatibility and how this new protocol will affect future products. Grandcentrix is Germany’s largest systems integrator specialized in the end-to-end creation of digital products and services for the Internet of Things, Smart Home and Mobile Commerce, and we are excited to once again have Pascal come and present.

Get Reactive – Introduction to RxJava

November 12, 2015

@ Devoxx Belgium November 2015, Antwerp

The RxJava hype is still in full swing and almost everything gets Rxified. At least since the stable RxAndroid 1.0 release, it’s time to take RxAndroid seriously!

In this session, you will learn what RxJava is about, how to use it on Android and how RxAndroid can be used to build maintainable Android Apps from networking with Retrofit2 to UI with the new RxBinding and RxLifecycle libraries powered by MVP.

If you haven’t had the time to Get Reactive, we’ll provide a quick introduction why you should use RxAndroid in your current and next projects.

Material Design Introduction

February 9, 2015

@ mobile.cologne

(German) Introduction into Material Design, Androids new design language in Android Lollipop.